286 Natural-Historiml Collections. 



divLsion, we find the different groups very naturally allied, and it is only in their 

 arrangement that there is any thing to revise. 



The white-blooded animals are the mollusca, Crustacea, testacea, and insects. 

 This division, certainly, is not altogether irreproachable ; however there was not 

 a better till the time of Linnaus. Amongst the mollusca, Aristotle particularly 

 designates the Octopus, the Loligo, the Sepia, the Arganav4a, remarking that 

 this latter is not attached to its shell. He describes in detail all the parts of 

 these animals, and speaks even of their brain ; which is very remarkable, since 

 it is very few years ago that the existence of such an organ in the mollusca was 

 determined. 



The subdivisions which he establishes amongst the animals with white blood 

 are still better than his principal divisions ; in the insects, for example, it is al- 

 together the classification of Linnaus. He distinguishes the insects according as 

 they are winged or apterous ; and of the former composes three sub-orders, dis- 

 tinguished by having wings to the number of two or four, or having them covered 

 with horny cases {elytrw.') He then explains what he means by genus in zool- 

 ogy, and gives, as an example, the soUpeda, which he constitutes of the horse, 

 the ass, and the wild mule of Syria {nemmius.) It is indeed a perfectly isolat- 

 ed genus, and one of those which we would at the present day select for illustra- 

 tion. 



Aristotle, after this introduction, which is presented, as he himself remarks, as 

 a bait to lure towards the study of natural history, passes to the description of the 

 different parts of animals, commencing with the human body, which serves him for 

 a term of comparison, and for the base of his nomenclature. He treats first of the 

 great regions, and of all that is external ; then he passes to the examination of 

 the internal parts. There his observations ceased to be so exact. However, 

 the great features of organization were well known to him, and he even appears 

 to have been better informed on some details than most of those who have 

 followed him. He knew, for instance, the Eustachian tube, and speaks of it in 

 the passage where he refutes Alcmeon, who contended, as we before stated, that 

 goats respire by the ears. He commences his descriptions with the brain, and 

 states, that this organ is found in all red-blooded animals without exception ; but 

 that, amongst white-blooded animals, it is only found in the mollusca. Man, he 

 adds, of all animals, possesses the most voluminous brain. He describes very 

 well the two membranes which envelope this organ, and the different nerves which 

 leave it to be distributed to the eye. But to this single point all his neurological 

 knowledge was confined ; he was ignorant both of the distribution and use of the 

 nerves. Herophilus was the first who had somewhat exact ideas on this part of 

 anatomy. Aristotle speaks of the veins whose principal trunks have their origin 

 in the heart ; he distinguishes well the venae cavae from the pulmonary vein ; he 

 describes also the aorta from its origin to its division at the inferior part of the 

 trunk. But he did not know tliat the arteries contain blood ; and seems to 

 have thought that the air penetrates to the heart, an organ which he describes as 

 having only three cavities. He treats of the stomach, the omentum, the liver, 

 the spleen, the bladder, the kidneys and their appendages ; he says that the right 

 kidney is placed higher than the left. All these descriptions, although incom- 

 plete, and even false in many points, prove at least that he had seen the viscera of 

 which he speaks. 



Aristotle next occupies himself more particularly with animals, and first speaks 

 of their limbs. In describing those of the elephant, he remarks, how the length of 

 the fore-legs, and the nature of the joints, render it diflicult for this animal to drink 

 and to gather nourishment from the earth ; he shows that the trunk supplies this 

 inconvenience, and becomes an useful organ of prehension. Moreover he 

 knew that this trunk is a true nose. He continues, and gives very interesting 

 details on the modes of reproduction of this quadruped, on the differences of the 

 sexes, &c. Buffon has contradicted him on many points, but almost always in, 

 correctly, as is proved by the observations recently made in India, 



